History of Thermo King Reefer Units.

The power of electricity jump-started modern refrigeration, but keeping things cool began centuries earlier. Civilizations in Greece, China and Italy piled winter snows deep inside mountain caves and buried food in the cold stuff. By the 1800s, ice blocks ruled, but they didn’t ride well in wagons, carts and railroad cars. Even newfangled manufactured ice of the early 1900s had trouble handling cross-country hauls. An American inventor, Fred Jones, developed the first mechanized cooling systems designed to chill tractor trailers, and his 1939 Thermo King patent launched refrigerated transportation history.

 

Little known fact, Fred Jones, mentioned in the article is a black man; super smart and forward thnking. Give credit where credit is due.
Think about Fred Jones, next time you ride your snowmobile. Yep, he built the first one using an old airplane body and propeller.
Fought in WW1 in France.

 

It says Bombardier invented it in 1937.
Fred Jones , built a snow machine to convey doctors to patients across the frozen fields. This was sometime between 1912 - 1930 when he lived in Hallock, Minnesota. Problem is he didn't get a patent on it so didn't get credit for inventing it.